The present invention relates generally to a reel clamping device, particularly to a reel clamping device which is capable of positioning a reel rapidly and precisely.
A reel is often used in a sheet supply mechanism of a packaging machine in which, a continuous strip of wrapping sheet is wound on the reel to supply the packaging machine with wrapping sheets. However, an exchange of two reels of different size is often needed during the process of manufacture, and the middle of the new reel has to be disposed exactly where that of the old one was. For this reason, the clamping and the positioning of a new reel is time-consuming, and expertise of the operator is required.
A reel clamper is disclosed in the Japanese Pat. Publication Gazette with No. Sho 62-167919. FIG. 1 is a cross-sectional view showing the construction of the reel clamper; and FIG. 2 is an exploded perspective view showing the construction of the reel clamper. As shown in FIGS. 1 and 2, the reel clamper comprises a cylindrical shell 102 which is provided with a plurality of through slots 101; a screw bolt 103 with two different threaded end portions 103a, 103b; a stopper 104 mated to the threaded end portion 103a; and a base 105 mated to the threaded end portion 103b. A slider 106 is disposed around the small end portion of the stopper 104, and three jaws 107 are pivotally connected to the slider 106. Three jaws 108 are fixed onto the base 105. Because the threaded portions 103a and 103b have different thread directions, the stopper 104 and the base 105 will be driven to move toward or apart from each other when the screw bolt 103 is driven to rotate by means of a handle 109. When the handle 109 is rotated, the rubber ring 106b disposed around the slider 106 will hinder the slide of the slider 106 during which the jaws 107 retract or protrude, and the jaws 107 and 108 accommodated within the slots 101 will be driven to move together with the stopper 104 and the base 105 along the axis of the screw bolt 103. Under this circumstance, the jaws 107 will be conducted by the inclined surface 104a of the stopper 104 to move radially outward and urge one end portion of the reel 110 (see FIG. 1) so that the jaws 107 will incorporate with the jaws 108 to clamp the reel 110 firmly. Reels clamped by such a clamper will be precisely positioned if the position of the base 105 relative to the screw bolt 103 is well adjusted before operation of the clamper. However, the jaws 107 must retract into the slots 101 of the shell 102 before the reel 110 can be removed from the shell 102, and the operator must rotate the handle 109 several turns to replace an old reel with a new one.